Apparatus for improving combustion in fuel burners



Feb. 18, 1930. J. G. DUDLEY 1,747,229

APPARATUS FOR IMPROVING GOMBUSTION IN FUEL BURNERS Filed Jan. 17. 1928 INVENTOR MA ATTORNEY vPatented Feb. 18, 1930 UNITED STATES PATENT OFFICE JAMES G. DUDLEY, OF WES'II.` ENGLEWOOD, NEW JERSEY Application filed January 17, 1928. Serial No. 247,386.

My present invention relates to a method and apparatus for securing efficient and substantially complete combustion of fuel used in furnaces and more particularly is directed to procuring complete combustion of coal in furnaces used in connection with hand-fired boilers and house heating systems in general.

In the present types of furnace construction, the sro-called firing door of such furnaces is usually supplied with a damper slide. ri'Chis functions as a check upon the amount of t raft through the coal bed within the furnace. In present practice, the slide upon being opened, admits cold air to enter into the interior of the furnace without any preheating of any kind. This results diminishing the draft through the coal bed as the air ordinarily seekinoi to enter the furnace beneath the grate when the firing door slide damper is shut is, instead, sucked into the furnace above the grate and coal bed. However, the incoming air beinof relatively cold, it mixes mechanically, only, with the unburnt combustible gases distilling off from the coal bed and is discharged into the chimney Where it is lost, and with a consequent loss in fuel efficiency. It follows, then, that an efficient damper for furnaces of the firing door type should not only admit air for draft diminishing purposes, but also supply air in a heated state of sufficiently high temperatures to chemically combine in the combustion Zone of the furnace, with the unburnt combustible gases distilling off from the coal bed and thus secure substantially complete combustion of the constituents of the fuel and, therefore greater fuel efficiency.

The method and apparatus disclosed lherein have as their main object the modification of, and improvement in, present furnace construction and consequent operation, whereby complete combustion of the fuel utilized therein is obtained by permittingthe introduction therein of a preheated air supply for n' completing' combustion of the combustible gases in the combustion zone of such furnaces. i

Another important object of my present novel method and apparatus is to provide means in an economical form whereby auxiliary air supplied to the combustion space of a furnace may be superheated to about the temperature of the burning gases so that the air thus supplied completes the combustion of the combustible gases above the coal bed by 55, readily combining therewith, thus economizing in fuel and increasing the efciency of the furnace to which my method and apparatus are applied.

Another obj ect of my invention is to provide an air superheating structure which may be readily adapted and attached to the firing doors of present day furnaces, the structure thereof being in substance in the customary standards, of universal type, so that with slight variations of the attaching parts of my superheater, the device, as an attachment, is readily mounted into operative position in a furnace at small installation expense.

Another object of my invention disclosed herein is to provide a superheating apparatus so mounted on the interior of the ring door of a furnace as to be located within the combustion zone of such furnace, thereby to be brought to high temperatures, due to its association with the fire bed therein, and whereby the provision of a suitable fire resistant porous retardant, such as mineral or steel wool, carefully packed within the interior of my superheating apparatus the velocity of incoming air with its charge of oxygen is retarded, and permit-ted to be infiltrated through the retardant, and by the time it has reached -the interior of the combustion zone the incoming air is highly heated and readily combines chemically with the unconsumed combustible gases within said Zone,

Other objects of the invention are to improve generally the simplicity and efficiency of such devices and to provide a method and apparatus of this kind which is economical, durable and reliable in operation without care, economical to manufacture and easy to install.

I desire it to be understood that this invention is not limited to any specific form or arrangement of parts or steps except in so far as such limitations are specified in theclaims.

Referring to the accompanying drawing in lo which like characters of reference indicate the same parts in the different views:

Fig. 1 is a sectional view along line 1-1 in Fig. 2 looking in the direction of the arrows.

Fig. 2 is a view of the air superheater from the interior of the furnace.

In Fig. 1, the furnace door .3, comprising a standard type of construction, including the door mounted slide damper 17 with its pivotally mounted control knob 18 whereby the openings 18 may be opened or closed, and the usual formainous bale plate 5 held by sleeve bolts 11 to the door are all of the usual standard. To this is attached my device, which comprises in its present preferred form of construction an inner mounted mesh wire covering 2. This covering is fitted to the door in such a manner as to completely cover 2G? the baiiie plate all over, Within the door. The

mesh is attached to the door by removing the usual sleeve bolts 11, putting on the mesh and then replacing said bolts 11 thereby to hold the mesh and baille, as shown in Fig. 1 tightly together in the baffle plate position.

After my device is applied, as hereinafter described, all that part of the mesh wire 2, not covered by the base portion of my device when in operative pos-ition, is covered by a fire resisting facing of cement X, thereby sealing all air entrance through the door to the furnace interior to thereby compel all incoming air, through apertures 18, to pass through my apparatus. The mesh 2, therefore, serves as a mechanical means to bond the sealing cement to the baiile plate 5, to compel all entering air to go through the superheating device.

The superheating device comprises a foraminous base plate 6, preferably circular in outline, slightly conveXed at its center, over which is mounted a substantially bell-shaped air-retarding material container 7, having an annular attaching flange 12. This flange may be provided with a rabbeted seat wherein to nestably receive the base plate 6, whereby simple attaching means, later to be described, may hold both plate 6 and container 7 in operative position.

The container 7 is aflixed to the plate 6 and held rigidly in place by L-shaped anchor bolts 15 bolted to the door 3 by nuts 20. These bolts pass through the apertures 16 in the plate 5, the L-shaped portion engaging and holding the flange 12 of the container, and anchoring same in position. This is an important feature of myV invention as it is by this contrivance that I can speedily affix the entire assembly to the conventional furnace door by drilling, if necessary, the holes 16 in suitable location. The container isrprovided with a cylindrical duct having inner and outwardly extended outlets denoted by 8 and 9 respectively. The container and duct are filled with closely packed steel wool 10 or other equivalent air entangling and retarding material. Mineral wool has also been found to be satisfactory for this purpose and it is among the possibilities that an extremely porous fire refractory body may be used for the same purpose. It is necessary for such an air entangling and retarding body to be completely porous throughout its mass so as to permit the passage of air therethrough while retarding its velocity. Then the device is in operation, the association of this device with the interior combustion space Z of the furnace causes the container and its retardant to become extremely hot, thereby to superheat the infiltrating air passing therethrough, to the combustion space.

As a further means to retard the travel of the air and for heating the same, and also for more generally dispersing incoming air to prevent stratification, there is provided interiorly of the device and as an open cap for the outlet portion 9, a concave cap 13, which is suitably mounted to the plate 6 by a shouldered bolt 1A in spaced relation to the outer edge of the outlet port. The cap being present in the combustion space of the heater also becomes hot and acts to return the incoming air slightly backwardly, and to disperse and dilfuse the superheated air throughout the rising, incompletely combusted gases from the iire bed C, as shown by the stream lines A, Fig. 1.

The operation of my apparatus and method is as follows:

Then the damper 17 is opened, relatively cold air rushes in from the atmosphere through the apertures 18, in the usual manner. The air then passes through the apertures 16 in the foraminous plate 5. So far the action isconventional. The cement facing X causes all incoming air to be directed through the container 7 and its preheating retardant 10, as shown by the arrows.

It will be observed that the porous retardant is disposed in the combustion zone Z of the furnace. The entire assembly, container, diffusion cap and retardant become so highly heated that when the passing air has emerged into the combustion zone it has practically reached the combustion temperature of the furnace gases. The superheated air is then diffused by the cap 18 in a path shown by the arrows A, and the dotted lines D. The highly heated air mixes with and thereby brings the unconsumed combustible gases rising from the coal a fresh supply of superheated atmospheric oxygen causing subtsantially complete combustion to take place within the combustion Zone Z thereby eliminating all smoke and waste of useful fuel.

It will readily be seen that the fire may burn more slowlydue to diminished draft and yet give olf greater heat than under present construction and practice, because the partially combusted gases, heretofore discharged to atmosphere through the stack, are by my device fully burned, and all com bustible constituents therein utilized, effecting a great saving of fuel, as heretofore noted.

Thus, it will be seen that combustion of the combustible gases, heretofore not fully burned, is practically completed before the discharge thereof to the stack or chimney.

The embodiment illustrated is shown by way of preference only. The foregoing detailed description has been given for clearness of understanding. Hence no unnecessary limitation should be understood, but the appended claims should be construed as broadly as permissible in view of the prior art.

lVhat I claim is:

1. In combination, a furnace grate having coal thereon, a dampered firing door associated therewith adapted to supply air to said grate to reduce the draft through the coal on said grate, a foraminous base plate associated with said door, a meshed sheet associated with said foraminous base plate, a dome means having an outlet at one end associated with said foraminous base plate and sheet and providing a chamber therein, said dome means extending over said grate and coal, anchor means associated with said domeand door to rigidly afhx said dome and foraminous means to said door, a porous material disposed within said dome and adapted to be heated to the temperature of substantially that of the burning gases, and to retard and heat air flowing therethrough to said combustion gas temperature, a diffusing cap rigidly disposed in spaced relation to the outlet of said dome means adapted to diffuse the heated air coming from said outlet throughout the combustion Zone above said grate whereby unburned combustible gases arising from said coal on said grate are completely consumed, and a fire refractory cement affixed to said mesh whereby to completely close the passage of all air through said door except through said heating dome.

2. In an air heating device of the class described comprising a furnace door having air entering means therein comprising a manipulatable slide and a foraminous base plate, a wire mesh thereover, and an air preheating device interiorly afxed to said foraminous base and mesh means, and a fire refractory cement covering all of said mesh except that covered by the said air preheating means.

3. An air heater for a furnace, the latter having a fuel-feed door provided with a dampered cold air inlet normally closing a furnace fuel opening, said heater comprising a meshed sheet adapted to be disposed in said opening to completely close the same, a foraminous plate on one side of said sheet between the fire side of said door and said sheet, means to replaceably secure said sheet and plate to said door, a metallic dome having a foraminous base on the other side of said sheet, means associated with said door to secure said dome to said sheet, the interior of said dome being filled with an air retarding material, the end of said dome opposite said base being open and having one portion thereof extending into the interior of said dome and filled With said material, an arcuate cap spaced from said open end, and means to replaceably secure said cap to said base.

t. In combination, a furnace fuel feed door having flanged edges and a dampered cold air inlet, a foraminous plate replaceably secured to the fire side of said door and being spaced from and bounded by said flanged edges, a sheet of metallic mesh secured to and covering said foraminous plate on its fire side and extending to said edges, dome means providing an air superheating chamber therein secured to the fire side of said sheet, said cham'ber being filled with metallic wool, the fire side of said sheet being coated with fire-proof cement except where said side is covered by the dome.

5. An air heater for a furnace comprising, a dome shaped member having a hollow interior and open ends, one end being wider than the other, the narrow end being provided with a hollow, cylindrical member having open ends, a portion of said cylindrical member extending into said dome interior,

the remaining portion extending beyond the dome member, the apertured plate normally closing the wider end of said dome member, the interiors of said dome and cylindrical members being filled with metallic wool, an

acuate cap spaced from one end of said cylin. drical member and secure to said plate, a foraminous plate covering said apertured plate, and means to replaceably secure said dome member and foraminous plate to the fire side of a furnace door.

Signed at Hackensack, in the county of Bergen and State of New Jersey, this 11th day of January, 1928. v

JAMES G. DUDLEY. 

